This disclosure relates to a gas turbine engine, and more particularly to a vane for cooling thermal protection of a blade outer air seal (BOAS).
Gas turbine engines typically include a compressor section, a combustor section and a turbine section. During operation, air is pressurized in the compressor section and is mixed with fuel and burned in the combustor section to generate hot combustion gases. The hot combustion gases are communicated through the turbine section, which extracts energy from the hot combustion gases to power the compressor section and other gas turbine engine loads.
A typical turbine section includes at least one array of stator vanes and one array of BOAS each arranged circumferentially about an engine central longitudinal axis to define an outer radial flow path boundary for the hot combustion gases passing across exposed surfaces of the BOAS. Thus, the BOAS are prone to thermal distress due to the hot combustion gases. Each of the stator vanes includes an airfoil which communicates a relatively high pressure fluid downstream of the airfoil and onto an exposed surface of one of the BOAS, making a portion of the exposed surface especially prone to thermal distress.
Typically, BOAS are cooled by communicating bleed air from the compressor section to an inner plenum of the BOAS, which results in a parasitic loss due to gases being heated by the compressor section but not being combusted. The BOAS are cooled along the entire circumferential direction because the relative circumferential position of each of the upstream vane airfoil segments and relative position of combustor fuel nozzle locations may be unknown. Accordingly, a localized cooling feature is desirable to minimize parasitic losses.